Question

The isoelectronic pair of ions is

• A. $S{c}^{2+}$ and $V^{3+}$
• B. $M{n}^{2+}$ and $F{e}^{3+}$
• C. $M{n}^{3+}$ and $F{e}^{2+}$
• D. $N{i}^{3+}$ and $F{e}^{2+}$

Answer 1

Answer: (B)

The isoelectronic species are those species which have same number of electrons.
(a) $S{c}^{2+}$ and $V^{3+}$
Number of electrons in $S{c}^{2+}=19$
Number of electrons in $V^{3+}=21$
(b) $M{n}^{2+}$ and $F{e}^{3+}$
Number of electrons in $M{n}^{2+}=23$
Number of electrons in $F{e}^{3+}=23$
(c) $M{n}^{3+}$ and $F{e}^{2+}$
Number of electrons in $M{n}^{3+}=22$
Number of electrons in $F{e}^{2+}=24$
(d) $N{i}^{3-}$ and $F{e}^{2-}$
Number of electrons in $N{i}^{3-}=31$
Number of electrons in $F{e}^{2-}=28$
Thus, $M{n}^{2+}$ and $F{e}^{3+}$ are isoelectronic pair